Hello,Is there a way I can see which computers are sending/receiving data on my wireless network?

I am on a secure wireless network and my only wireless computer is off, but my wlan light on my router is blinking like crazy.

I use windows machines xp and vista.

I just wanted to know if this is a router thing because I am transferring data via ethernet or if someone is using my wireless network

The MAC address of any computer connected in any way to your router will show up in its settings which you can access through Internet Explorer by typing it's address into the URL bar. You can also, if you wish, make your wireless computer the only one allowed and you can hide the SSID so the network doesn't show to the outside world and change the security key for added peace if mind

From my own understanding it's a bad idea because anyone installing a new wifi network won't be able to spot instantly which channels are already in use.

As I recall from earlier discussions it can cause you problems with connecting.

As far as security is concerned anyone with any interest in hacking will know how to spot a wifi network even if the SSID is not broadcast. I think even an ultra common utility like NetStumbler will uncover you.